CA2122879A1 - Scouring compounds and method - Google Patents
Scouring compounds and methodInfo
- Publication number
- CA2122879A1 CA2122879A1 CA002122879A CA2122879A CA2122879A1 CA 2122879 A1 CA2122879 A1 CA 2122879A1 CA 002122879 A CA002122879 A CA 002122879A CA 2122879 A CA2122879 A CA 2122879A CA 2122879 A1 CA2122879 A1 CA 2122879A1
- Authority
- CA
- Canada
- Prior art keywords
- weight
- mixture
- stripping composition
- coated surface
- stripping
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
Links
- 238000000034 method Methods 0.000 title claims abstract description 39
- 150000001875 compounds Chemical class 0.000 title claims description 12
- 238000009991 scouring Methods 0.000 title 1
- 239000000203 mixture Substances 0.000 claims abstract description 131
- 238000000576 coating method Methods 0.000 claims abstract description 52
- 239000011248 coating agent Substances 0.000 claims abstract description 44
- 238000005507 spraying Methods 0.000 claims abstract description 11
- 238000011084 recovery Methods 0.000 claims abstract description 7
- 239000007767 bonding agent Substances 0.000 claims abstract description 5
- 239000000126 substance Substances 0.000 claims abstract description 4
- QTBSBXVTEAMEQO-UHFFFAOYSA-N Acetic acid Chemical compound CC(O)=O QTBSBXVTEAMEQO-UHFFFAOYSA-N 0.000 claims description 21
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 18
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 claims description 15
- 239000003973 paint Substances 0.000 claims description 15
- 229920000663 Hydroxyethyl cellulose Polymers 0.000 claims description 13
- 239000004354 Hydroxyethyl cellulose Substances 0.000 claims description 13
- 235000019447 hydroxyethyl cellulose Nutrition 0.000 claims description 13
- OKKJLVBELUTLKV-UHFFFAOYSA-N Methanol Chemical compound OC OKKJLVBELUTLKV-UHFFFAOYSA-N 0.000 claims description 12
- CDBYLPFSWZWCQE-UHFFFAOYSA-L Sodium Carbonate Chemical compound [Na+].[Na+].[O-]C([O-])=O CDBYLPFSWZWCQE-UHFFFAOYSA-L 0.000 claims description 12
- 230000003472 neutralizing effect Effects 0.000 claims description 9
- YXFVVABEGXRONW-UHFFFAOYSA-N Toluene Chemical compound CC1=CC=CC=C1 YXFVVABEGXRONW-UHFFFAOYSA-N 0.000 claims description 8
- XMGQYMWWDOXHJM-JTQLQIEISA-N (+)-α-limonene Chemical compound CC(=C)[C@@H]1CCC(C)=CC1 XMGQYMWWDOXHJM-JTQLQIEISA-N 0.000 claims description 6
- SECXISVLQFMRJM-UHFFFAOYSA-N N-Methylpyrrolidone Chemical compound CN1CCCC1=O SECXISVLQFMRJM-UHFFFAOYSA-N 0.000 claims description 6
- 239000003795 chemical substances by application Substances 0.000 claims description 6
- 229910000029 sodium carbonate Inorganic materials 0.000 claims description 6
- 229920003091 Methocel™ Polymers 0.000 claims description 4
- ISWSIDIOOBJBQZ-UHFFFAOYSA-N Phenol Chemical compound OC1=CC=CC=C1 ISWSIDIOOBJBQZ-UHFFFAOYSA-N 0.000 claims description 4
- NEHMKBQYUWJMIP-NJFSPNSNSA-N chloro(114C)methane Chemical compound [14CH3]Cl NEHMKBQYUWJMIP-NJFSPNSNSA-N 0.000 claims description 4
- 239000012188 paraffin wax Substances 0.000 claims description 4
- UDSFAEKRVUSQDD-UHFFFAOYSA-N Dimethyl adipate Chemical compound COC(=O)CCCCC(=O)OC UDSFAEKRVUSQDD-UHFFFAOYSA-N 0.000 claims description 3
- MUXOBHXGJLMRAB-UHFFFAOYSA-N Dimethyl succinate Chemical compound COC(=O)CCC(=O)OC MUXOBHXGJLMRAB-UHFFFAOYSA-N 0.000 claims description 3
- XTDYIOOONNVFMA-UHFFFAOYSA-N dimethyl pentanedioate Chemical compound COC(=O)CCCC(=O)OC XTDYIOOONNVFMA-UHFFFAOYSA-N 0.000 claims description 3
- 239000004094 surface-active agent Substances 0.000 claims description 3
- 239000002966 varnish Substances 0.000 claims description 3
- 239000011449 brick Substances 0.000 claims description 2
- 239000004568 cement Substances 0.000 claims description 2
- 238000005406 washing Methods 0.000 claims description 2
- 239000002023 wood Substances 0.000 claims description 2
- 239000002253 acid Substances 0.000 claims 1
- 230000002378 acidificating effect Effects 0.000 claims 1
- 238000007790 scraping Methods 0.000 description 6
- 239000007921 spray Substances 0.000 description 5
- 229910000831 Steel Inorganic materials 0.000 description 3
- 239000010959 steel Substances 0.000 description 3
- GWEVSGVZZGPLCZ-UHFFFAOYSA-N Titan oxide Chemical compound O=[Ti]=O GWEVSGVZZGPLCZ-UHFFFAOYSA-N 0.000 description 2
- 239000000654 additive Substances 0.000 description 2
- 238000004140 cleaning Methods 0.000 description 2
- 210000003298 dental enamel Anatomy 0.000 description 2
- 238000009472 formulation Methods 0.000 description 2
- 231100001261 hazardous Toxicity 0.000 description 2
- 239000004922 lacquer Substances 0.000 description 2
- 239000004816 latex Substances 0.000 description 2
- 229920000126 latex Polymers 0.000 description 2
- 239000011253 protective coating Substances 0.000 description 2
- 230000001681 protective effect Effects 0.000 description 2
- 239000002699 waste material Substances 0.000 description 2
- 210000002268 wool Anatomy 0.000 description 2
- 230000001680 brushing effect Effects 0.000 description 1
- 239000003518 caustics Substances 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 238000001035 drying Methods 0.000 description 1
- 239000002320 enamel (paints) Substances 0.000 description 1
- 238000003912 environmental pollution Methods 0.000 description 1
- 239000004744 fabric Substances 0.000 description 1
- 239000012530 fluid Substances 0.000 description 1
- 239000000383 hazardous chemical Substances 0.000 description 1
- 239000004615 ingredient Substances 0.000 description 1
- 150000002500 ions Chemical class 0.000 description 1
- JEIPFZHSYJVQDO-UHFFFAOYSA-N iron(III) oxide Inorganic materials O=[Fe]O[Fe]=O JEIPFZHSYJVQDO-UHFFFAOYSA-N 0.000 description 1
- 230000000873 masking effect Effects 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 231100000252 nontoxic Toxicity 0.000 description 1
- 230000003000 nontoxic effect Effects 0.000 description 1
- 239000002245 particle Substances 0.000 description 1
- 239000004033 plastic Substances 0.000 description 1
- 239000004575 stone Substances 0.000 description 1
- 239000004408 titanium dioxide Substances 0.000 description 1
- 231100000331 toxic Toxicity 0.000 description 1
- 230000002588 toxic effect Effects 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
- C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
- C09D9/00—Chemical paint or ink removers
- C09D9/04—Chemical paint or ink removers with surface-active agents
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B24—GRINDING; POLISHING
- B24C—ABRASIVE OR RELATED BLASTING WITH PARTICULATE MATERIAL
- B24C1/00—Methods for use of abrasive blasting for producing particular effects; Use of auxiliary equipment in connection with such methods
- B24C1/08—Methods for use of abrasive blasting for producing particular effects; Use of auxiliary equipment in connection with such methods for polishing surfaces, e.g. smoothing a surface by making use of liquid-borne abrasives
- B24C1/086—Descaling; Removing coating films
-
- C—CHEMISTRY; METALLURGY
- C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
- C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
- C09D9/00—Chemical paint or ink removers
-
- C—CHEMISTRY; METALLURGY
- C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
- C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
- C09D9/00—Chemical paint or ink removers
- C09D9/005—Chemical paint or ink removers containing organic solvents
-
- C11D2111/14—
Abstract
Disclosed herein is a method for the removal of coating films from a coated surface comprising the steps of: (a) pressure spraying a chemical stripping composition onto a coated surface having at least one coating film to be removed, the stripping composition comprising a bonding agent whereby the consistency of the stripping composition will be such that it will effectively cling to the surface regardless of the orientation of the surface; (b) waiting a sufficient amount of time for the stripping composition to strip the coating from the surface and to form a mixture of stripping composition and stripped coating film(s); (c) recovering the mixture by applying a vacuum source to aspirate the mixture into a recovery container. Also disclosed are novel and sprayable stripping compositions useful for removing coating films.
Description
FIELD OF THE lNV~ ION
1. BACKGROUND OF THE INVENTION
The present invention relates to a method for the removal of coating films such as paints, varnishes, lacquers, enamels, etc., from a coated surface. More specifically, the invention relates to a method of applying stripping compositions to various coated surfaces and in subsequent steps removing and recovering the resulting mixture of stripping compositions and stripped coatings. The method of the present invention is efficacious with a wide variety of coatings over a wide range of operating temperatures.
1. BACKGROUND OF THE INVENTION
The present invention relates to a method for the removal of coating films such as paints, varnishes, lacquers, enamels, etc., from a coated surface. More specifically, the invention relates to a method of applying stripping compositions to various coated surfaces and in subsequent steps removing and recovering the resulting mixture of stripping compositions and stripped coatings. The method of the present invention is efficacious with a wide variety of coatings over a wide range of operating temperatures.
2. PRIOR ART
A wide variety of coating removal compositions are known in the art. The chemical formulations will usually be tailored to work best on specific types of coatings such as latex paints, oil-based paints, varnishes, lacquers, enamels, etc. For example, an alkaline composition most useful for removing latex paints is disclosed in U.S. Patent No. 4,594,176.
Contemporary stripping formulations have been developed to minimize total workplace exposure to the vapours generated by the stripping compositions and concomitantly to minimize the toxic effects and environmental pollution caused by the stripping composition. Nevertheless, even if the stripping compositions are themselves biodegradable or non-toxic, they will become intimately mixed with many hazardous substances contained in the coatings being removed. For example, many paint coatings contain lead and other additives such as titanium dioxide which are considered to be hazardous for human health and for the environment.
Traditionally, stripping compositions are applied with a brush, a cloth or other similar means.
Such application methods are convenient for flat horizontal surfaces but become unwieldy and awkward when used to apply stripping compositions to ornamented, sculptured, vertical or upside down surfaces such as ceilings. In those situations it is difficult to apply the stripping composition evenly and without excessive drips. This results in much of the stripping compositions being wasted and dripping or running onto surfaces which are not meant to be stripped of their coatings.
The actual stripping operations are equally untidy. In accordance with the prior art, once the stripping composition has achieved its purpose, i.e. to dislodge the coating(s), the mixture of stripping composition and stripped coating(s) is usually scraped off as a gelatinous mass with the help of a scraping tool. Steel wools or similar tools are also used. In most instances the mixture of stripped residue is collected in drop sheets disposed below the surface being stripped. The scraping operation is also difficult to 8 ~ ~
_ -- 3 perform on uneven or ornamented surfaces. Furthermore, scraping movements with sharp instruments will oftentimes scratch or gouge the surface being stripped and the coating which is to be removed may remain in those scratches or gouges. While it may be possible in some instances to attempt to rinse off the mixture of stripping composition and stripped coating, such method could result in a run off of hazardous residues.
To resolve the difficulties noted above, it is an object of the present invention to provide a novel and advantageous method of applying, removing and recovering a mixture of stripping composition and stripped coating(s), such method being useful for the removal of coatings on various types of surfaces including wood, metal, brick, cements, stone, plastic, and fiberglas.
More specifically, the method disclosed herein minimizes waste of stripping composition, enables the stripping composition to be applied evenly even on inclined, textured or ornamented surfaces without dripping. The novel method also allows rapid and tidy recovery of the resulting mixture of stripping composition and stripped coating(s).
The present invention also provides improved stripping compositions which can, inter alia, effectively be used with the method of the present invention.
SUMMARY OF THE INVENTION
The invention provides a method for the removal of coating films from a coated surface comprising the steps of:
(a) pressure spraying a chemical stripping composition onto a surface having at least one coating film to be removed, the stripping composition comprising a bonding agent whereby the consistency of the stripping composition will be such that it will effectively cling to the surface regardless of the orientation of the surface;
(b) waiting a sufficient amount of time for the stripping composition to strip the coating from the surface and to form a mixture of stripping composition and stripped coating film(s);
(c) recovering the mixture by applying vacuum means to aspirate the mixture into a recovery container.
One embodiment of the invention provides a sprayable composition for the removal of coating films comprising a mixture of the following compounds:
2-10 weight % of sodium carbonate peroxydrate, 90-95 weight % of water, and 1-3 weight % of hydroxyethylcellulose.
One embodiment of the invention provides a sprayable composition for the removal of coating films comprising a mixture of the following compounds:
15-30 weight % of sodium hydroxide, 70-85 weight % of water, and 1-4 weight % of hydroxyethylcellulose.
One embodiment of the invention provides a sprayable composition for the removal of coating films comprising a mixture of the following compounds:
70-85 weight % methyl chloride, 1-5 weight % paraffin, 1-5 weight % toluol, 2-8 weight % methanol, 1-5 weight % methocel @ 4 m, 4-8 weight % nomyl phenol ethoxylate, 1-5 weight % acetic acid 99.5% concentration (glacial), and 1-5 % water.
Another embodiment of the present invention provides a sprayable composition for the removal of coating films comprising a mixture of the following compounds:
30-50 weight % n-methyl-2-pyrrolidone, 20-25 weight % d-limonene, 5-10 weight % di-methyl glutarate, 5-10 weight % di-methyl adipate, 5-10 weight % di-methyl succinate, and the remaining consisting of a surfactant.
Other features and advantages of the invention will become apparent to those of ordinary skill in the art upon review of the following detailed description, claims, and drawings.
~12287~
DETAILED DESCRIPTION
A preferred embodiment of the present invention will now be described for illustrative purposes.
In carrying out the present invention, a coating removal composition is firstly pressure sprayed on the surface having one or more coatings to be removed.
Advantageously, the pressure spraying apparatus will be fully portable so that it may be used outdoors. In a most preferred embodiment, a portable generator such as a HONDA model EG5000 XKIC (trade-mark) will provide electrical power to an air compressor such as a QUINCY
model QTSP-3-20 (trade-mark). The air compressor is connected with suitable hoses to a pressurized container such as a SHARPE 7530 (trade-mark), of a 2~ gallons capacity, which will have been previously loaded with a suitable stripping composition. The pressurized container is connected to a remote spray gun with suitable hoses. The spray gun will preferably be a SHARPE model 975Pl-10-70 (trade-mark). The spray gun is provided with a trigger, a spreader adjustment valve, a stripping composition delivery adjustment valve, and an air pressure adjustment screw. Such adjustment means will allow the person applying the stripping composition to adjust the spraying parameters, such as pressure, the flow of stripping composition, distance from the surface and spreading pattern in order to minimize avoid overspray and to provide even coverage on the entire surface to be stripped of its coating film(s). It is to 212~879 be understood that the stripping compositions useful in conjunction with the method of the present invention will be of such consistency so as to coat surfaces on which they are sprayed with minimal runs or drips. To achieve the required consistency, most commercially available stripping compositions will need to be modified by additives such as suitable bonding agents, for example hydroxyethyl cellulose, which will allow the stripping composition to cling to the surfaces on which they are sprayed. Examples of suitably modified stripping compositions are as follows:
(1) a sprayable composition for the removal of coating films comprising a mixture of the following compounds:
70-85 weight % methyl chloride, 1-5 weight % paraffin, 1-5 weight % toluol, 2-8 weight % methanol, 1-5 weight % methocel @ 4 m, 4-8 weight % nomyl phenol ethoxylate, 1-5 weight % acetic acid 99.5% concentration (glacial), and 1-5 % water; and (2) a sprayable composition for the removal of coating films comprising a mixture of the following compounds:
30-50 weight % n-methyl-2-pyrrolidone, 20-25 weight % d-limonene, 5-10 weight % di-methyl glutarate, 5-10 weight % di-methyl adipate, 5-10 weight % di-methyl succinate, and the remaining consisting of a surfactant.
It is to be understood that those skilled in the art can derive other suitable compositions without deporting from the spirit of the present invention.
Consequently, textured, ornamented, inclinedor even upside down surfaces can be quickly coated with the stripping compositions. Those skilled in the art of pressure spraying fluids will understand that by using overspray shields or masking techniques, detailed spraying can be accomplished around surfaces or objects which are not targeted for coating removal. It is also to be understood that all safety and precautionary measures will be taken to protect workers and the environment during these operations. For example, it is important for all workers to wear safety helmets, goggles, suits and footwear. Nearby shrubbery or vehicles should be covered with drop cloths.
Once the stripping composition has been applied, the worker(s) will let the stripping composition accomplish its task of breaking down and separating the coating film(s) from the coated surface. The amount of time required for this process will of course depend on various factors such as the nature of the stripping composition being used, the type of coating film(s) to be removed, the operating temperature, etc. Ideally, the amount of time will be less than half an hour.
2l2~879 When the stripping process is satisfactorily completed, the mixture of stripping composition and stripped coating film(s) will continue to adhere to the coated surface.
The mixture of stripping composition and stripped coating film(s) is then recovered with a wet/dry industrial vacuum such as model 2D15DS. By using a sufficiently strong vacuum with a suitably shaped intake nozzle, the mixture is cleanly and quickly lifted off the surface leaving the surface essential free of stripping composition and the stripped coating film(s). The mixture is recovered in suitable containers which may be transported elsewhere for safe disposal. Those skilled in stripping operations will appreciate that applying vacuum to the mixture leaves the previously coated surface unscathed from scraping tools or steel wools which could scratch or gouge the surface. Another important advantage is the tidy recovery of the mixture.
Furthermore, when a relatively quick drying stripping composition is used, the vacuuming operation will effectively dry the stripping composition and the recovery containers will essentially be filled with a dry mixture of particles removed coating film(s).
To ensure even further protection of the workplace environment, longitudinal reservoirs, and drop sheets placed between the surface being stripped and the reservoirs, are placed below the surface being stripped.
The reservoirs will collect any overspay of stripping ~122879 composition and will collect any subsequently sprayed product. The reservoirs therefore perform a task akin to a rain gutter. The reservoirs are linked to the vacuum by suitable hoses which will continously drain the reservoirs.
It is to be understood that the above steps may need to be repeated for surfaces having different, overlaid, coating films which require different stripping composition for their removal.
10Depending on the stripping composition being used, it may be advantageous to neutralize the stripping composition after its recovery. For example, if the stripping composition is a caustic composition such as follows: 15-30 weight % of sodium hydroxide, 1570-85 weight % of water, 1-4 weight % of hydroxyethyl cellulose, a convenient neutralizing agent such as:
15-30 weight % acetic acid at 99.5% concentration (glacial), and 70-85 weight % water will be sprayed onto the mixture of stripping composition and stripped coating film(s) to effectively bring the PH of the mixture to a normal level. For this neutralizing step, the same pressure spraying equipment can be used.
As an optional additional step, the stripped surface can be washed under high pressure spray with a suitable washing solution such as for example, sodium carbonate peroxydrate 2-10 % by weight, water 90-95% by weight, and hydroxyethyl cellulose, 1-3 % by weight.
~ 1~28~
The following are illustrative examples of the process of the present invention.
EXPERIMENTAL
Example 1 The exterior of an old clapboard house had previously and repeatedly been painted with oil-based paints, at various times over the years. The coats of paints had blistered, bubbled and chipped in various locations. The method of the present invention was applied to strip the boards from their paint so as to provide a proper surface on which to apply a protective coating. Workers used ladders and scaffolding to pressure spray a stripping composition to the surface of the boards. By using protective shields, areas of the house which did not required stripping were protected from any overspray.
The stripping composition comprised the following ingredients: 15-30 weight % of sodium hydroxide, 70 85 weight % of water, and 1-4 weight % of hydroxyethyl cellulose. The stripping composition had a consistency such that it clung to the boards with minimal dripping.
The composition was left to work for approximately 25 minutes. After that time the stripping composition had effectively broken down the paint layers which formed a mixture with the stripping composition.
~12~8~9 The mixture was then recovered by applying a vacuum source generated from an industrial vacuum. The mixture was effectively lifted off the boards without any requirement for scraping or rubbing. The recovered mixture was dumped into secure containers for shipment to a suitable waste disposal agency.
The surface of the boards was then neutralized by pressure spraying a neutralizing agent composed of:
15-30 weight % acetic acid at 99.5% concentration (glacial), and 70-85 weight % water to effectively bring the PH of the mixture to a normal level.
The stripped boards where then pressure washed with a cleaning composition to restore their original colour. The cleaning composition comprised the following: sodium carbonate peroxydrate 2-10 % by weight, water 90-95% by weight, and hydroxyethyl cellulose, 1-3 % by weight.
The board where then left to dry. The boards had been essentially restored to their natural appearance.
Example 2:
An oak railing, bannister and staircase with sculpted motifs had been painted with layers of oil-based paints. The method of the present invention was used to strip the paint layers to restore the oak to its original appearance. The stripping and neutralizing compositions 8~7~
described in Example l above where used. The entire process effectively remove the paint layers even from the crevices of the sculpted motifs. The entire process was accomplished in a fraction of the time that would have been required by conventional methods of brushing on and scraping stripping compounds and the overall process was more tidy and achieve good results especially in the portions of the railings having sculpted motifs.
Example 3:
A mechanically activated railway switching apparatus made of steel had been painted on numerous occasions with a protective enamel paint. Nevertheless, rust had formed and caused the paint to chip or bubble in various areas. As a result, the operation of the switching apparatus was hindered. In accordance with the method of the present invention a stripping composition such as in Examples 1 and 2 was pressure sprayed onto the components of the switching apparatus. After approximately one half hour the mixture of stripping composition and stripped paint wasaspirated and was transported elsewhere for safe disposal. The neutralizing agent of the Examples 1 and 2 was pressure sprayed. The switching apparatus components were then ready for an application of protective coating.
Although the invention has been described above with respect with one specific form, it will be evident to a person skilled in the art that it may be modified and refined in various ways. It is therefore wished to have it understood that the present invention should not be limited in scope, except by the terms of the following claims.
A wide variety of coating removal compositions are known in the art. The chemical formulations will usually be tailored to work best on specific types of coatings such as latex paints, oil-based paints, varnishes, lacquers, enamels, etc. For example, an alkaline composition most useful for removing latex paints is disclosed in U.S. Patent No. 4,594,176.
Contemporary stripping formulations have been developed to minimize total workplace exposure to the vapours generated by the stripping compositions and concomitantly to minimize the toxic effects and environmental pollution caused by the stripping composition. Nevertheless, even if the stripping compositions are themselves biodegradable or non-toxic, they will become intimately mixed with many hazardous substances contained in the coatings being removed. For example, many paint coatings contain lead and other additives such as titanium dioxide which are considered to be hazardous for human health and for the environment.
Traditionally, stripping compositions are applied with a brush, a cloth or other similar means.
Such application methods are convenient for flat horizontal surfaces but become unwieldy and awkward when used to apply stripping compositions to ornamented, sculptured, vertical or upside down surfaces such as ceilings. In those situations it is difficult to apply the stripping composition evenly and without excessive drips. This results in much of the stripping compositions being wasted and dripping or running onto surfaces which are not meant to be stripped of their coatings.
The actual stripping operations are equally untidy. In accordance with the prior art, once the stripping composition has achieved its purpose, i.e. to dislodge the coating(s), the mixture of stripping composition and stripped coating(s) is usually scraped off as a gelatinous mass with the help of a scraping tool. Steel wools or similar tools are also used. In most instances the mixture of stripped residue is collected in drop sheets disposed below the surface being stripped. The scraping operation is also difficult to 8 ~ ~
_ -- 3 perform on uneven or ornamented surfaces. Furthermore, scraping movements with sharp instruments will oftentimes scratch or gouge the surface being stripped and the coating which is to be removed may remain in those scratches or gouges. While it may be possible in some instances to attempt to rinse off the mixture of stripping composition and stripped coating, such method could result in a run off of hazardous residues.
To resolve the difficulties noted above, it is an object of the present invention to provide a novel and advantageous method of applying, removing and recovering a mixture of stripping composition and stripped coating(s), such method being useful for the removal of coatings on various types of surfaces including wood, metal, brick, cements, stone, plastic, and fiberglas.
More specifically, the method disclosed herein minimizes waste of stripping composition, enables the stripping composition to be applied evenly even on inclined, textured or ornamented surfaces without dripping. The novel method also allows rapid and tidy recovery of the resulting mixture of stripping composition and stripped coating(s).
The present invention also provides improved stripping compositions which can, inter alia, effectively be used with the method of the present invention.
SUMMARY OF THE INVENTION
The invention provides a method for the removal of coating films from a coated surface comprising the steps of:
(a) pressure spraying a chemical stripping composition onto a surface having at least one coating film to be removed, the stripping composition comprising a bonding agent whereby the consistency of the stripping composition will be such that it will effectively cling to the surface regardless of the orientation of the surface;
(b) waiting a sufficient amount of time for the stripping composition to strip the coating from the surface and to form a mixture of stripping composition and stripped coating film(s);
(c) recovering the mixture by applying vacuum means to aspirate the mixture into a recovery container.
One embodiment of the invention provides a sprayable composition for the removal of coating films comprising a mixture of the following compounds:
2-10 weight % of sodium carbonate peroxydrate, 90-95 weight % of water, and 1-3 weight % of hydroxyethylcellulose.
One embodiment of the invention provides a sprayable composition for the removal of coating films comprising a mixture of the following compounds:
15-30 weight % of sodium hydroxide, 70-85 weight % of water, and 1-4 weight % of hydroxyethylcellulose.
One embodiment of the invention provides a sprayable composition for the removal of coating films comprising a mixture of the following compounds:
70-85 weight % methyl chloride, 1-5 weight % paraffin, 1-5 weight % toluol, 2-8 weight % methanol, 1-5 weight % methocel @ 4 m, 4-8 weight % nomyl phenol ethoxylate, 1-5 weight % acetic acid 99.5% concentration (glacial), and 1-5 % water.
Another embodiment of the present invention provides a sprayable composition for the removal of coating films comprising a mixture of the following compounds:
30-50 weight % n-methyl-2-pyrrolidone, 20-25 weight % d-limonene, 5-10 weight % di-methyl glutarate, 5-10 weight % di-methyl adipate, 5-10 weight % di-methyl succinate, and the remaining consisting of a surfactant.
Other features and advantages of the invention will become apparent to those of ordinary skill in the art upon review of the following detailed description, claims, and drawings.
~12287~
DETAILED DESCRIPTION
A preferred embodiment of the present invention will now be described for illustrative purposes.
In carrying out the present invention, a coating removal composition is firstly pressure sprayed on the surface having one or more coatings to be removed.
Advantageously, the pressure spraying apparatus will be fully portable so that it may be used outdoors. In a most preferred embodiment, a portable generator such as a HONDA model EG5000 XKIC (trade-mark) will provide electrical power to an air compressor such as a QUINCY
model QTSP-3-20 (trade-mark). The air compressor is connected with suitable hoses to a pressurized container such as a SHARPE 7530 (trade-mark), of a 2~ gallons capacity, which will have been previously loaded with a suitable stripping composition. The pressurized container is connected to a remote spray gun with suitable hoses. The spray gun will preferably be a SHARPE model 975Pl-10-70 (trade-mark). The spray gun is provided with a trigger, a spreader adjustment valve, a stripping composition delivery adjustment valve, and an air pressure adjustment screw. Such adjustment means will allow the person applying the stripping composition to adjust the spraying parameters, such as pressure, the flow of stripping composition, distance from the surface and spreading pattern in order to minimize avoid overspray and to provide even coverage on the entire surface to be stripped of its coating film(s). It is to 212~879 be understood that the stripping compositions useful in conjunction with the method of the present invention will be of such consistency so as to coat surfaces on which they are sprayed with minimal runs or drips. To achieve the required consistency, most commercially available stripping compositions will need to be modified by additives such as suitable bonding agents, for example hydroxyethyl cellulose, which will allow the stripping composition to cling to the surfaces on which they are sprayed. Examples of suitably modified stripping compositions are as follows:
(1) a sprayable composition for the removal of coating films comprising a mixture of the following compounds:
70-85 weight % methyl chloride, 1-5 weight % paraffin, 1-5 weight % toluol, 2-8 weight % methanol, 1-5 weight % methocel @ 4 m, 4-8 weight % nomyl phenol ethoxylate, 1-5 weight % acetic acid 99.5% concentration (glacial), and 1-5 % water; and (2) a sprayable composition for the removal of coating films comprising a mixture of the following compounds:
30-50 weight % n-methyl-2-pyrrolidone, 20-25 weight % d-limonene, 5-10 weight % di-methyl glutarate, 5-10 weight % di-methyl adipate, 5-10 weight % di-methyl succinate, and the remaining consisting of a surfactant.
It is to be understood that those skilled in the art can derive other suitable compositions without deporting from the spirit of the present invention.
Consequently, textured, ornamented, inclinedor even upside down surfaces can be quickly coated with the stripping compositions. Those skilled in the art of pressure spraying fluids will understand that by using overspray shields or masking techniques, detailed spraying can be accomplished around surfaces or objects which are not targeted for coating removal. It is also to be understood that all safety and precautionary measures will be taken to protect workers and the environment during these operations. For example, it is important for all workers to wear safety helmets, goggles, suits and footwear. Nearby shrubbery or vehicles should be covered with drop cloths.
Once the stripping composition has been applied, the worker(s) will let the stripping composition accomplish its task of breaking down and separating the coating film(s) from the coated surface. The amount of time required for this process will of course depend on various factors such as the nature of the stripping composition being used, the type of coating film(s) to be removed, the operating temperature, etc. Ideally, the amount of time will be less than half an hour.
2l2~879 When the stripping process is satisfactorily completed, the mixture of stripping composition and stripped coating film(s) will continue to adhere to the coated surface.
The mixture of stripping composition and stripped coating film(s) is then recovered with a wet/dry industrial vacuum such as model 2D15DS. By using a sufficiently strong vacuum with a suitably shaped intake nozzle, the mixture is cleanly and quickly lifted off the surface leaving the surface essential free of stripping composition and the stripped coating film(s). The mixture is recovered in suitable containers which may be transported elsewhere for safe disposal. Those skilled in stripping operations will appreciate that applying vacuum to the mixture leaves the previously coated surface unscathed from scraping tools or steel wools which could scratch or gouge the surface. Another important advantage is the tidy recovery of the mixture.
Furthermore, when a relatively quick drying stripping composition is used, the vacuuming operation will effectively dry the stripping composition and the recovery containers will essentially be filled with a dry mixture of particles removed coating film(s).
To ensure even further protection of the workplace environment, longitudinal reservoirs, and drop sheets placed between the surface being stripped and the reservoirs, are placed below the surface being stripped.
The reservoirs will collect any overspay of stripping ~122879 composition and will collect any subsequently sprayed product. The reservoirs therefore perform a task akin to a rain gutter. The reservoirs are linked to the vacuum by suitable hoses which will continously drain the reservoirs.
It is to be understood that the above steps may need to be repeated for surfaces having different, overlaid, coating films which require different stripping composition for their removal.
10Depending on the stripping composition being used, it may be advantageous to neutralize the stripping composition after its recovery. For example, if the stripping composition is a caustic composition such as follows: 15-30 weight % of sodium hydroxide, 1570-85 weight % of water, 1-4 weight % of hydroxyethyl cellulose, a convenient neutralizing agent such as:
15-30 weight % acetic acid at 99.5% concentration (glacial), and 70-85 weight % water will be sprayed onto the mixture of stripping composition and stripped coating film(s) to effectively bring the PH of the mixture to a normal level. For this neutralizing step, the same pressure spraying equipment can be used.
As an optional additional step, the stripped surface can be washed under high pressure spray with a suitable washing solution such as for example, sodium carbonate peroxydrate 2-10 % by weight, water 90-95% by weight, and hydroxyethyl cellulose, 1-3 % by weight.
~ 1~28~
The following are illustrative examples of the process of the present invention.
EXPERIMENTAL
Example 1 The exterior of an old clapboard house had previously and repeatedly been painted with oil-based paints, at various times over the years. The coats of paints had blistered, bubbled and chipped in various locations. The method of the present invention was applied to strip the boards from their paint so as to provide a proper surface on which to apply a protective coating. Workers used ladders and scaffolding to pressure spray a stripping composition to the surface of the boards. By using protective shields, areas of the house which did not required stripping were protected from any overspray.
The stripping composition comprised the following ingredients: 15-30 weight % of sodium hydroxide, 70 85 weight % of water, and 1-4 weight % of hydroxyethyl cellulose. The stripping composition had a consistency such that it clung to the boards with minimal dripping.
The composition was left to work for approximately 25 minutes. After that time the stripping composition had effectively broken down the paint layers which formed a mixture with the stripping composition.
~12~8~9 The mixture was then recovered by applying a vacuum source generated from an industrial vacuum. The mixture was effectively lifted off the boards without any requirement for scraping or rubbing. The recovered mixture was dumped into secure containers for shipment to a suitable waste disposal agency.
The surface of the boards was then neutralized by pressure spraying a neutralizing agent composed of:
15-30 weight % acetic acid at 99.5% concentration (glacial), and 70-85 weight % water to effectively bring the PH of the mixture to a normal level.
The stripped boards where then pressure washed with a cleaning composition to restore their original colour. The cleaning composition comprised the following: sodium carbonate peroxydrate 2-10 % by weight, water 90-95% by weight, and hydroxyethyl cellulose, 1-3 % by weight.
The board where then left to dry. The boards had been essentially restored to their natural appearance.
Example 2:
An oak railing, bannister and staircase with sculpted motifs had been painted with layers of oil-based paints. The method of the present invention was used to strip the paint layers to restore the oak to its original appearance. The stripping and neutralizing compositions 8~7~
described in Example l above where used. The entire process effectively remove the paint layers even from the crevices of the sculpted motifs. The entire process was accomplished in a fraction of the time that would have been required by conventional methods of brushing on and scraping stripping compounds and the overall process was more tidy and achieve good results especially in the portions of the railings having sculpted motifs.
Example 3:
A mechanically activated railway switching apparatus made of steel had been painted on numerous occasions with a protective enamel paint. Nevertheless, rust had formed and caused the paint to chip or bubble in various areas. As a result, the operation of the switching apparatus was hindered. In accordance with the method of the present invention a stripping composition such as in Examples 1 and 2 was pressure sprayed onto the components of the switching apparatus. After approximately one half hour the mixture of stripping composition and stripped paint wasaspirated and was transported elsewhere for safe disposal. The neutralizing agent of the Examples 1 and 2 was pressure sprayed. The switching apparatus components were then ready for an application of protective coating.
Although the invention has been described above with respect with one specific form, it will be evident to a person skilled in the art that it may be modified and refined in various ways. It is therefore wished to have it understood that the present invention should not be limited in scope, except by the terms of the following claims.
Claims (20)
1. A method for the removal of coating films from a coated surface comprising the steps of:
(a) pressure spraying a chemical stripping composition onto a coated surface having at least one coating film to be removed, said stripping composition comprising a bonding agent whereby the consistency of the stripping composition will be such that it will effectively cling to the surface regardless of the orientation of the surface;
(b) waiting a sufficient amount of time for the stripping composition to strip said coating from said surface and to form a mixture of stripping composition and stripped coating film(s);
(c) recovering said mixture by applying vacuum means to aspirate said mixture into a recovery container.
(a) pressure spraying a chemical stripping composition onto a coated surface having at least one coating film to be removed, said stripping composition comprising a bonding agent whereby the consistency of the stripping composition will be such that it will effectively cling to the surface regardless of the orientation of the surface;
(b) waiting a sufficient amount of time for the stripping composition to strip said coating from said surface and to form a mixture of stripping composition and stripped coating film(s);
(c) recovering said mixture by applying vacuum means to aspirate said mixture into a recovery container.
2. The method of claim 1 comprising the following additional step (d): neutralizing the previously coated surface by pressure spraying thereon a neutralizing agent, namely a base if the mixture is acidic or alternatively an acid if the mixture is basic.
3. The method of claim 2 comprising the following additional step (e): washing the previously coated surface by pressure spraying thereon a water based sodium carbonate peroxydrate solution.
4. The method of claim 1 or 2 comprising the additional step of recovering said spilled stripping composition and said neutralizing agent in reservoir means placed below said previously coated surface, said reservoir means being connected by a hose to said vacuum means.
5. The method of claim 1 wherein said coated surface is wood.
6. The method of claim 1 wherein said coated surface is metallic.
7. The method of claim 1 wherein said coated surface is cement.
8. The method of claim 1 wherein said coated surface is brick.
9. The method of any of the preceding claims wherein at least one coating film is paint.
10. The method of any of claims 1 to 7 wherein at least one coating film is varnish.
11. The method of any of claims 1 to 7 wherein said bonding agent is hydroxyethyl cellulose.
12. The method of claim 9 wherein said hydroxyethyl cellulose is present at 1-4 weight % of the stripping composition.
13. The method of any of claims 1 to 7, wherein said stripping composition comprises:
2-10 weight % of sodium carbonate peroxydrate, 90-95 weight % of water, and 1-3 weight % of hydroxyethylcellulose.
2-10 weight % of sodium carbonate peroxydrate, 90-95 weight % of water, and 1-3 weight % of hydroxyethylcellulose.
14. The method of claim 2 wherein said stripping composition comprises:
15-30 weight % of sodium hydroxide, 70-85 weight % of water, 1-4 weight % of hydroxyethylcellulose, and said neutralizing agent comprises:
15-30 weight % acetic acid at 99.5% concentration (glacial), and 70-85 weight % water.
15. The method of any of claims 1 to 7, wherein said stripping composition comprises:
70-85 weight % methyl chloride, 1-5 weight % paraffin, 1-5 weight % toluol, 2-8 weight % methanol, 1-5 weight % methocel @ 4 m, 4-8 weight % nomyl phenol ethoxylate, 1-5 weight % acetic acid 99.5% concentration (glacial), and 1-5 % water.
15-30 weight % acetic acid at 99.5% concentration (glacial), and 70-85 weight % water.
15. The method of any of claims 1 to 7, wherein said stripping composition comprises:
70-85 weight % methyl chloride, 1-5 weight % paraffin, 1-5 weight % toluol, 2-8 weight % methanol, 1-5 weight % methocel @ 4 m, 4-8 weight % nomyl phenol ethoxylate, 1-5 weight % acetic acid 99.5% concentration (glacial), and 1-5 % water.
16. A sprayable composition for the removal of coating films comprising a mixture of the following compounds:
2-10 weight % of sodium carbonate peroxydrate, 90-95 weight % of water, and 1-3 weight % of hydroxyethylcellulose .
2-10 weight % of sodium carbonate peroxydrate, 90-95 weight % of water, and 1-3 weight % of hydroxyethylcellulose .
17. A sprayable composition for the removal of coating films comprising a mixture of the following compounds:
15-30 weight % of sodium hydroxide, 70-85 weight % of water, and 1-4 weight % of hydroxyethylcellulose.
15-30 weight % of sodium hydroxide, 70-85 weight % of water, and 1-4 weight % of hydroxyethylcellulose.
18. A sprayable composition for the removal of coating films comprising a mixture of the following compounds:
70-85 weight % methyl chloride, 1-5 weight % paraffin, 1-5 weight % toluol, 2-8 weight % methanol, 1-5 weight % methocel @ 4 m, 4-8 weight % nomyl phenol ethoxylate, 1-5 weight % acetic acid 99.5% concentration (glacial), and 1-5 % water.
70-85 weight % methyl chloride, 1-5 weight % paraffin, 1-5 weight % toluol, 2-8 weight % methanol, 1-5 weight % methocel @ 4 m, 4-8 weight % nomyl phenol ethoxylate, 1-5 weight % acetic acid 99.5% concentration (glacial), and 1-5 % water.
19. A sprayable composition for the removal of coating films comprising a mixture of the following compounds:
30-50 weight % n-methyl-2-pyrrolidone,
30-50 weight % n-methyl-2-pyrrolidone,
20-25 weight % d-limonene, 5-10 weight % di-methyl glutarate, 5-10 weight % di-methyl adipate, 5-10 weight % di-methyl succinate, and the remaining consisting of a surfactant.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA002122879A CA2122879A1 (en) | 1994-05-04 | 1994-05-04 | Scouring compounds and method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA002122879A CA2122879A1 (en) | 1994-05-04 | 1994-05-04 | Scouring compounds and method |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2122879A1 true CA2122879A1 (en) | 1995-11-05 |
Family
ID=4153536
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002122879A Abandoned CA2122879A1 (en) | 1994-05-04 | 1994-05-04 | Scouring compounds and method |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA2122879A1 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6117829A (en) * | 1996-12-03 | 2000-09-12 | Solutia Inc. | Dibasic ester gel/paste composition and use of same for removing polysulfide and other chemicals from substrates |
-
1994
- 1994-05-04 CA CA002122879A patent/CA2122879A1/en not_active Abandoned
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6117829A (en) * | 1996-12-03 | 2000-09-12 | Solutia Inc. | Dibasic ester gel/paste composition and use of same for removing polysulfide and other chemicals from substrates |
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